The efficacy of nutritional supplements for the adjunctive treatment of schizophrenia in adults: A systematic review and network meta-analysis

Nutraceuticals and phytoceuticals in the treatment of schizophrenia: a systematic review and network meta-analysis

Background

Sub-optimal response in schizophrenia is frequent, warranting augmentation strategies over treatment-as-usual (TAU).

Methods

We assessed nutraceuticals/phytoceutical augmentation strategies via network meta-analysis. Randomized controlled trials in schizophrenia/schizoaffective disorder were identified via the following databases: PubMed, MEDLINE, EMBASE, Scopus, PsycINFO, CENTRAL, and ClinicalTrials.gov. Change (Standardized Mean Difference=SMD) in total symptomatology and acceptability (Risk Ratio=RR) were co-primary outcomes. Secondary outcomes were positive, negative, cognitive, and depressive symptom changes, general psychopathology, tolerability, and response rates. We conducted subset analyses by disease phase and sensitivity analyses by risk of bias and assessed global/local inconsistency, publication bias, risk of bias, and confidence in the evidence.

Results

The systematic review included 49 records documenting 50 studies (n=2,384) documenting 22 interventions. Citicoline (SMD=-1.05,95%CI=-1.85; -.24), L-lysine (SMD=-1.04,95%CI=-1.84;-.25), N-acetylcysteine (SMD=-.87,95%CI=-1.27;-.47) and sarcosine (SMD=-.5,95%CI=-.87-.13) outperformed placebo for total symptomatology. High heterogeneity (tau2=.10, I2=55.9%) and global inconsistency (Q=40.79, df=18, p=.002) emerged without publication bias (Egger's test, p=.42). Sarcosine improved negative symptoms (SMD=-.65, 95%CI=-1.10; -.19). N-acetylcysteine improved negative symptoms (SMD=-.90, 95%CI=-1.42; -.39)/general psychopathology (SMD=-.76, 95%CI=-1.39; -.13). No compound improved total symptomatology within acute phase studies (k=7, n=422). Sarcosine (SMD=-1.26,95%CI=-1.91; -.60), citicoline (SMD=-1.05,95%CI=-1.65;-.44), and N-acetylcysteine (SMD=-.55,95%CI=-.92,-.19) outperformed placebo augmentation in clinically stable participants. Sensitivity analyses removing high-risk-of-bias studies confirmed overall findings in all phases and clinically stable samples. In contrast, the acute phase analysis restricted to low risk-of-bias studies showed a superior effect vs. placebo for N-acetylcysteine (SMD=-1.10,95%CI=-1.75,-.45), L-lysine (SMD=-1.05,95%CI=-1.55,-.19), omega-3 fatty acids (SMD=-.83,95%CI=-1.31,-.34) and withania somnifera (SMD=-.71,95%CI=-1.21,-.22). Citicoline (SMD=-1.05,95%CI=-1.86,-.23), L-lysine (SMD=-1.04,95%CI=-1.84,-.24), N-acetylcysteine (SMD=-.89,95%CI=-1.35,-.43) and sarcosine (SMD=-.61,95%CI=-1.02,-.21) outperformed placebo augmentation of TAU ("any phase"). Drop-out due to any cause or adverse events did not differ between nutraceutical/phytoceutical vs. placebo+TAU.

Conclusions

Sarcosine, citicoline, and N-acetylcysteine are promising augmentation interventions in stable patients with schizophrenia, yet the quality of evidence is low to very low. Further high-quality trials in acute phases/specific outcomes/difficult-to-treat schizophrenia are warranted.

Inflammatory markers of symptomatic remission at 6 months in patients with first-episode schizophrenia

Neuroinflammation contributes to the pathophysiology of various mental illnesses including schizophrenia. We investigated peripheral inflammatory cytokines as a biomarker for predicting symptomatic remission in patients with first-episode schizophrenia. The study included 224 patients aged 15-60 years who fulfilled the criteria for schizophrenia spectrum disorder with a treatment duration ≤6 months. Serum levels of tumor necrosis factor (TNF) -α, interferon-γ, interleukin (IL)-1α, IL-1β, IL-6, IL-8, IL-10, and IL-12 were measured. Psychotic symptoms, depressive symptoms, and general functioning were assessed using the Positive and Negative Syndrome Scale, Beck Depression Inventory (BDI), Calgary Depression Scale for Schizophrenia, and Personal and Social Performance scale, respectively. Duration of untreated psychosis (DUP) was also recorded. We investigated the factors associated with remission for each sex in logistic regression analysis. In total, 174 patients achieved remission at the 6-month follow-up (females, 83.5%; males, 70.9%). Remission was associated with older age and lower BDI scores in male patients and with lower TNF-α levels and shorter DUP in female patients. Our findings suggest that peripheral inflammatory cytokines may impede early symptomatic remission in female patients with schizophrenia. In addition, depressive symptoms in males and long DUP in females may be poor prognostic factors for early remission in patients with first-episode psychosis.

Omega-3 index as risk factor in psychiatric diseases: a narrative review

Numerous studies have described associations between the omega-3 index (defined as the RBC percentage of EPA and DHA) and mental conditions, but no risk stratification or target value has gathered consensus so far. This narrative review aims to summarize the published data on the association between omega-3 index and mental illness and to contribute to the concept of an omega-3 index in the field of mental health. The bibliographic searches have been carried out in PubMed, Scopus and Web of Science databases to find relevant English language original research studies related to that association. The study search and selection process were registered in a PRISMA flow. Thirty-six studies were included in this review examining the links between omega-3 index and postpartum depression (3), major depression (15), major depression and bipolar disorder (1), bipolar disorder (4), schizophrenia and major depression (1), schizophrenia and other psychosis (5) and dementia (7). Thirty of these studies found either significant differences in omega-3 index between patients and controls or inverse relationships between omega-3 index and disease severity. The published evidence is compelling enough to suggest omega-3 index as a risk factor for some psychiatric diseases, specifically, major depression, postpartum depression, psychosis, and dementia. In occidental populations, we propose a risk threshold of (a) 4-5% in major depression and dementia, (b) 5% in postpartum depression, and (c) 4% for psychosis transition.

Complementary/Integrative Medicine Treatment and Prevention of Youth Psychosis

The rationale for CIM treatments in youth psychoses is to optimize treatment by targeting symptoms not resolved by antipsychotics, such as negative symptoms (major drivers of disability). Adjunctive omega-3 fatty acids (ω-3 FA) or N-acetyl cystine (NAC usage for > 24-week) can potentially reduce negative symptoms and improve function. ω-3 FA or exercise may prevent progression to psychosis in youth (in prodromal stage). Weekly 90-minute moderate to vigorous physical activity or aerobic exercise can reduce positive and negative symptoms. Awaiting better research, CIM agents are also recommended because they are devoid of any serious side-effects.

Unsaturated Fatty Acids in Mental Disorders: An Umbrella Review of Meta-Analyses

Unsaturated fatty acids might be involved in the prevention of and improvement in mental disorders, but the evidence on these associations has not been comprehensively assessed. This umbrella review aimed to appraise the credibility of published evidence evaluating the associations between unsaturated fatty acids and mental disorders. In this umbrella review, systematic reviews and meta-analyses of studies comparing unsaturated fatty acids (including supplementation, dietary intake, and blood concentrations) in participants with mental disorders with healthy individuals were included. We reanalyzed summary estimates, between-study heterogeneity, predictive intervals, publication bias, small-study effects, and excess significance bias for each meta-analysis. Ninety-five meta-analyses from 29 systematic reviews were included, encompassing 43 studies on supplementation interventions, 32 studies on dietary factors, and 20 studies on blood biomarkers. Suggestive evidence was only observed for dietary intake, in which higher intake of fish was associated with reduced risk of depression (RR: 0.78; 95% CI: 0.69, 0.89) and Alzheimer disease (RR: 0.74; 95% CI: 0.63, 0.87), and higher intake of total PUFAs might be associated with a lower risk of mild cognitive impairment (RR: 0.71; 95% CI: 0.61, 0.84). Evidence showed that PUFA supplementation was favorable but had weak credibility in anxiety, depression, attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), dementia, mild cognitive impairment, Huntington's disease, and schizophrenia (P-random effects <0.001-0.040). There was also weak evidence on the effect of decreased circulating n-3 (ɷ-3) PUFAs among patients on risk of ADHD, ASD, bipolar disorder, and schizophrenia (P-random effects <10-6-0.037). Our results suggest that higher levels of unsaturated fatty acids may relieve symptoms or reduce the risk of various mental disorders; however, the strength of the associations and credibility of the evidence were generally weak. Future high-quality research is needed to identify whether PUFA interventions should be prioritized to alleviate mental disorders.